U.S. Frost Dates by Weather Station

NOAA station USC00364214 · Pennsylvania

Frost Dates for Indiana, PA

NOAA weather station Indiana 3 SE (USC00364214), Pennsylvania · elevation 1102 ft (336 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 24only 1 spring in 10 still has a frost later
  • Typical last frostMay 850% chance of a frost after it
  • Typical first fall frostOctober 1350% chance of a frost before it
  • Frost-free season157 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Indiana, PASpring: a frost after April 23 in 9 years out of 10, after May 8 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 13 in half of the years, before October 27 in 9 years out of 10. Typical frost-free season: 157 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 8First frost ~Oct 13Frost season at Indiana, PASpring: a frost after April 23 in 9 years out of 10, after May 8 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 13 in half of the years, before October 27 in 9 years out of 10. Typical frost-free season: 157 days.JFMAMJJASONDLast frost ~May 8First frost ~Oct 13
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 24October 1
50% (typical)May 8October 13
90% (likely)April 23October 27
Frost-free season (32°F, 50% chance)
157 days
Hard frost (28°F), last in spring, 50% chance after
April 27
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost May 6 (2 days earlier than the 30-year normal), typical first fall frost October 22 (9 days later). Frost-free season 168 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring at Indiana: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 24, 20% May 19, 30% May 15, 40% May 11, 50% May 8, 60% May 5, 70% May 1, 80% April 28, 90% April 23. Observed last spring frost in recent years: 2021 May 14, 2022 May 1, 2023 April 28, 2024 April 24, 2025 May 11, 2026 May 4.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 24May 8Apr 232021: May 142022: May 12023: April 282024: April 242025: May 112026: May 4Fall at Indiana: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 5, 30% October 7, 40% October 10, 50% October 13, 60% October 16, 70% October 19, 80% October 23, 90% October 27. Observed first fall frost in recent years: 2021 November 3, 2022 October 9, 2023 October 23, 2024 October 11, 2025 October 18.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 13Oct 272021: November 32022: October 92023: October 232024: October 112025: October 18
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021May 14November 3
2022May 1October 9
2023April 28October 23
2024April 24October 11
2025May 11October 18
2026May 4season not over yet

What these dates mean

October 1 marks the cautious fall date for finishing the harvest of tender crops in Indiana, Pennsylvania, when there is only a 10 % chance that a light frost has arrived earlier.

The 50% dates, May 8 for spring and October 13 for fall, indicate the points where a light frost has an even chance of occurring later (spring) or earlier (fall); they are not frost dates themselves. For a cautious plan, the spring light-frost date is May 24, which carries a 10 % chance of frost later, while the fall cautious date is October 1 with a 10 % chance of frost earlier. The median hard-frost dates are April 27 and October 25, and a hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, making it the more severe threat.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after May 24" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before October 1" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Indiana, PANumbered nearest stations: 1 — near Ford City, PA — 22 mi; 2 — Ebensburg, PA — 22 mi; 3 — Salina, PA — 23 mi; 4 — near Patton, PA — 30 mi; 5 — Altoona, PA — 35 mi.25 mi · 40 km1. near Ford City, PA — 22 mi12. Ebensburg, PA — 22 mi23. Salina, PA — 23 mi34. near Patton, PA — 30 mi45. Altoona, PA — 35 mi5
  1. near Ford City, PA 22 mi (36 km)
  2. Ebensburg, PA 22 mi (36 km)
  3. Salina, PA 23 mi (37 km)
  4. near Patton, PA 30 mi (48 km)
  5. Altoona, PA 35 mi (56 km)

Sources

* Hardiness zone 6b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.5972, -79.1186.